Tire mold



Patented Jan. 25, 19,27.

PATENT oFFIcE.

UNITED STATES 'mom-.is MIDGLEY, 'or HA'rlrDnN,

COMPANY. or cmcornn FALLS, cnosnr'rs.

Application led April 2, 1924. Serial No. 703,578.

In one manner of vulcanizing tire cas` ings they are enclosed between the halves of circumferentially split moldswhich are stacked one upon another and held closed 6 against the expansive force of fluid pressure or the resistance of a rigid core by a hydraulic ram. The molds heretofore used for this purpose have been made of cast iron, or cast or forged steel. The present invention relates to -molds adapted for use in this old manner but constructed out of sheet metal. The main objects are the incorporation by suitable design in a sheet steel mold of a sufiicient amount of the strength and vrigidity of the former solid metal molds, and of their adaptability for use in the present type of heater and on horizontal loading and unloading conveyors,

with the lightness and low steam consumption of sheet metal Construction. The invention involves certain broad conceptions and additional 4details of construction which will be pointed out below. y

Referring now to the drawings, in which molds constructed according to my invention' will be described in several embodiments, v

Fig. 1 is a section, moved, and Fig. 2 is a fragmentary side elevation, of one form of mold constructed according to the principles of my invention;

Figs. 3 and 4 are similar views of a second variation;

Figs. 5 and6 are similar views of a .third variation; 1 Fig. 7 is a fragmentary view of a fourth variation which may be similar, except as shown,toFi .5;

Figs. Sand 9 are similar views of a fifth variation; Y Figs.,10 and 11 are similar views of a -sixth variation;

Figs. 12 and 13 are similar viewsof a seventh variation; and

in use. In all, the side of the tire i's molg:

with one mold half re- A{Fig- 14 is a perspective of one form of.; clip used in holdingthebead rings togethl' ed by side plates of substantially uniform thickness, curved to tire shape. The tread pattern is molded on the tire'n some variants by a portion of the side wall formed in the reverse of the pattern desired, while in others it is formed by a separate piece attached to the side wall. In the preferred cases these tread molding portions. are in practical eifect continuations of the side Walls andof a thickness substantially uniform with the walls. Due to the depth of the pattern'the apparent thickness is greaterin these tread molding portions, but the efective thickness-the distance the heat must travel to reach the rubberis substantially 'the same as in the main part of the side walls. p The side plates in each of the illustrated cases has secured to it by suitable means bearing members upon which successive molds may be piled one on another in a stack, and through which the lateral pressure serving to keep the molds closed may be transmitted. These members, and their supporting means, are preferably arranged' as a perforate frame surrounding the side lates, protecting the latter and receiving the ateral pressure and yet ermitting the atmosphere of steam in w ich the stack of molds 1s immersed to reach and .contact directly with the uniform walled side plate The individual variant forms will now be described with particular reference to their own constructional details.

In Figs. 1 and 2 is shown a mold adapted for curing a plain tread tire on a rigid core. The core'20 ismade sectional if desired in anyv of the usual ways. the type shown being held together by binderrings 21 and bolts 22. The tire 23 Aisbuilt or placed onthe core in any desired way.' The side plates 24 are in this case formed with flanges 2,5 adapted to underlie the tire bead edges, and, there be.

ing no tread design, extend so as to meet 'at the parting line 26 fof the mold. Secured to spot welding or are rings 27. turned outwardly to form-flanges 28. At theA inner periphery of the side plates rings 29, having inwardly' projecting llanges 30, 'are secured to the inturned portions 25 in a similar manner. Bridging the space between flanges 28 and 30 are annular plates 31, shown-Fas secured in place by spot welding v,the outer periphery the side plates as by (and b'y folding at 32 if desired) to flange 28. This structure forms a frame enclosing struction the side plates are relieved r'of all crushing strain, being tensioned around the tire by the pressure of the rings 27 and 29 at their outer and inner peripheries, so that they are in tension rather than in compression and are not subject to buckling, a condition of importance in thin-walled sheet metal molds.

The frame formed by plate 31 and rings 27 and 29 is made perforate in order to permit direct access of steam to the side platesl In d the present case this is accomplished by` slits 34 (Fig. 2) cut in plates 31 at intervals, and holes 35 in rings 27 and 29. The transverse planes on which the right and left hand halves of Fig. 1, and similar views of later modifications, are taken are different so that while one half shows a.slot 34, the otherdoes not. In the form shown the flat plates 31 contact with the wide point of the', side plates, and may be spot welded or brazed in place. This construction gives a very rigid mold, the plate 31, the rings 27 and 29, and.

the side plates 23forming a truss work by which the strain exerted by the press ram is .taken up and distributed through the mold.

without buckling strains being created. Each of these parts, through their combined action, receives its share of theload, and the mold as a whole can stand a mold pressure -greater than -the allowable load for any of the width of rings 27 and 29, altho additional strength ofthe preferre the arts individually.

desired, however, the plates 31 may be separated from the side plates by incresiplg t e C011- struction will not be attained. In that case the space within each frame will be single, instead of being divided into two as inthe Villustrated form. These remarks apply are Athe usual'A whiclrmay be secured toequallyv to the other variants described below. In the form of Fig. 1, as well as in the others to be described, po'cketing 'of water of condensation is avoided by holes 36 drilled at intervals around the mold along lines where suchpockets would otherwise exist.

The form of mold shown in Fi 3 and 4 adapted for'tires havin a. moded tread pattern and vulcanized un er the expansive force'of a v fluid pressure ba 40. Thel base of the bag and the bead e of the tire shown asV confined by bead rings 41 of neiafivo through a split ring 45 having a tongue and v groove connection 46 with the iron part 44. When the ring is expanded into place it is held by a Wedge piece 47 (Fig. 4) and the sheet metal plate 43 is Welded or otherwise permanently secured to it. rIhis construction makes a firm union between all the parts mentioned.

The outer surfaces of pieces 44 are machined off at 48 to receive rings 49 having outwardly projecting iianges 50. rlfhe rings 49 are turned inwardly so as to form flanges 51 meeting :it the parting lineA of the mold and suitably shaped to form a part of the molding pattern. AIn the case shown the pattern necessitated a thinner construction at the edge of the left hand member 44 than is 'suitable for cast iron, and an insert piece of steel 52 has been shown to fill out the pattern atV this point. plates 43 have an angular bend 53 shaped.I to abut the outer surface ofthe bead rings 4l, and then extend parallel Withthe plane of the tire to form prying, flanges 54. Plates 55 extend from the iianges 50 tothe flanges 54, being bent at 56 to shift from one plane to the other, are secured to flange 50 by being folded at 57 around it, and secured to fiange 54 b y that fiange being folded at 58 around-the plate. At 59 a slight bend in xthis plane .is shown accommodating it to the curvature of'the sheet metal plates 43, to

castings take the place of both the mem bers 44 and/the rings 49, and are preferably drilled at 65 for steam circulation and drainage. These castings are secured by rings 45 to side plates 43 in a mannersimilar to that previouslydescrib'ed, and plates 55 are attached by bending around lugs 66 on the casting, likewise in a similar manner. In

this and other cases registration of the mold halves may be secured by plates or rings 67 secured to the periphery of the'mold and 'having intertitting portions causing the mold halves to register when they are pressed together. This construction is desirable when The sheet metal side 7 a construction is shown in' which isc.

4 Rings 75 are provi-ded with inwardly bentare held and forming 'a punched through the side plates to form the molding a tread pattern is used, but is not necessary in the case shown in Fig..1. The construction shown in Fig. 7 may be completed at the.inner circumference in the same manner astlie variant shown in Fig'. 3, or in a manner illustrated in any of the other figures.

filed August 28, 1923. Instead of qxtending inwardly in flanges 54 as in the earlier described case, the side plates in this embodiiiient terminate adjacent the bead of the tire and have bra-Zed or welded thereto rings 73 which are folded at 74 aiouiid the inwardly extending portions of plates 55, which are constructed in a sin ilai' manner to that earlier discussed. Another Vchange inade in this form is in the structure oi' the bead rings. Instead of being of the usual type made of castings, they are shown here as being constructed of sheet metal.

flanges 76 and 77, the former serving as prying flanges for separating the molds, and the latter as retaining flanges for holding the bead rings assembled. A convenient manner of holding the bead rings assembled is by a clip 78 illustrated in Fig. 14, being of U-shaped cross section with a pivot 79 adapted to be'secured to one of the flanges 77. By rotating this clip about its pivot its U-shaped portion can be caused tol einbrace the two flanges 77 when these are brought into adj acency, or can be swung to release the flanges and permit the bead 'rings 'to be separated. On the outer surface of rings 75 are rings 80, suitably formed as shown to receive the bead edges of the tire.

These rings may be secured to the rings 7 5` by spot Welding, riveting, or brazing, and may be formed by rolling a steel band or any other suitable method.

- In the variantshown in Figs. 8 and 9 the side` plates 81 are made heavy enough'so that the treadv pattern can be formed in them, and terminate slightly short of the bead edges of the tire in adjacency to bead rings 82 of `the usual construction,- which together by bolts 83. Secured to the side plates at their outer peripheries, backing for any holes pattern according to the disclosure in'my saidapplication Serial No. 659,813, filed August 28, 1923, are rings 84 bent outthe ln the variant shown in Figs 5 and 6,l several changes of construction have been wardly into flanges 85. The side plates are machinedflat at. 86 to receive plates 87, which may be spot welded or brazed to them and which are folded at v88 around the flanges 85. Additional plates 89 reinforce plates 87 at their inner'l portions, and abut the side plates in amanner indicated. These plates press, when the mold is assembled, against the flat sides of the bead rings 82, and may be held to the plates 87 by brazing or spot Welding and in addition by a fold 9 0 of the latter plates around them.

In the variant shown in- Fig. 10 the structure is quite similar to that shown in Fig. 5 with the exception that the side plate 91 is formed in this' instance with a thickened portion 92, in which the tread molding patv or otherwise secured at 93 to a short piece 94 i corresponding except in/ height to the piece 78 of Fig. 5. rIhe remaining parts are constructed in a manner similar to that indicated in Fig. 5, and are designated by the same numerals.

Another quite similar form of mold is shown in Figs. 12 and 13. The main feature of difference liesin the substitution of other fastening means for the pin 93 of the variant. This pin was made necessary by a difference in the materials of which the side late 91 and the member 94 were constructed so that Welding was impractical. In the structure shown in Fig. 12, an annular clip 97 is substituted for the member 94. This clip is folded tightly around both the inner circumference of the side plate 91, and the inner circumference of the late 55. v If this clip is tightly folded aroun these parts, no

other securing-means is necessary. It is dei looA 1. A mold adapted for use inthe vulcanization of tire casings, having side plates of substantially uniform thickness, curved. to

CTI

the shape of the tires, and bearing members spaced in part from the side plates but attached thereto at both the inner and outer peripheries of the mold and presenting surfaces upon which pressure may be received and transmitted through the 4mold Without buckling. p

2. A mold adapted for use in the vulcanization of tire casings, having side plates of subtantially uniformi thickness, curved to the shape of the tire, and carried by an enclosing Aframe presenting substantially dat surfaces extending parallel to the plane of the tire, upon which surfaces adjacent molds may rest When stacked one upon another,

saidv frame being made perforate so as to permit an enveloping atmosphere of steam to have free accessl to the side plates.`

3. A mold adapted for use in the vulcanization oftire casings, having side plates of Y substantially uniformthickness, curved to the shape of the tire, and substantially iat plates attached to the side plates'at about the outermost part of their curvature and extending parallel to the plane of the mold so as to be spaced from the side plates; said Lemme Y flat plates serving as supports for the molds when stacked one oveil another.

' 4. A mold adapted for use in the vulcanization of tire casings, having side plates of substantially uniform thickness, curved to the shape of the tire, substantially dat plates attached to the side plates at about the Widest part of the mold and ,extending parallel to the plane of the mold so as to be spaced from the side plates, .said :liat plates serving vas supports :for the molds when 'stacked one over another, and additienal devices for transmittin through the mold Without distorting the side plates 'the lateral pressure used in holding the molds assembled. Y

5. A mold adapted for use in the vulcanisation of tire casings7 having side plates of substantially uniform thickness, curved to the shape of the tire, and an open :trame permanently attached to -each side plate and forming therewith an 'annular truss Work imparting rigidity to the mold and capable Aoit transmitting-lateral pressure Without distorting the curved side plates.

y THOMAS XGLEY. 

